CN111944278B - Liquid crystal polymer composition - Google Patents

Abstract

The invention provides a liquid crystal polymer composition capable of forming articles such as molded articles with improved metal adhesion while maintaining welding strength. A liquid crystalline polymer composition comprising: 100 parts by mass of a liquid crystal polymer, 0.1 to 10 parts by mass of a cyclic olefin resin, and 0.1 to 5 parts by mass of a carbodiimide group-containing compound.

Description

Liquid crystal polymer composition

Technical Field

The present invention relates to a liquid crystal polymer composition capable of forming an article such as a molded product having improved metal adhesion while maintaining welding strength.

Background Art

Liquid crystal polymers are used not only in molded products but also in various applications such as fibers and films due to their excellent mechanical properties such as heat resistance and rigidity, chemical resistance, and dimensional accuracy. In particular, in the information and communication fields such as personal computers (PCs) and mobile phones (cell phones), the high integration, miniaturization, thin-walled, and low-profile (low-height) of components are developing rapidly, and there are many cases where very thin wall thickness parts of less than 0.5 mm are formed. The use of liquid crystal polymers has increased significantly by taking advantage of their excellent moldability, that is, good fluidity and no burrs, which are characteristics not found in other polymers.

However, liquid crystal polymers have the property that their molecules are easily oriented even with very little shear force, and their mechanical strength is also highly anisotropic in the flow direction (MD) and the direction perpendicular to it (TD) during molding. When there is a weld on the molded product, it is believed that there is a problem of weak strength of the weld.

In order to solve such a problem, for example, Patent Document 1 describes a method of improving the anisotropy and soldering strength of a liquid crystal polymer by including a cyclic olefin resin (also referred to as a cyclic olefin polymer or a cyclic olefin copolymer).

Prior art literature

Patent Literature

Patent document 1: Japanese Patent Application Laid-Open No. 10-316841.

Summary of the invention

Problems to be solved by the invention

However, when such a cyclic olefin-based resin is contained, the metal adhesion of the molded article is reduced, so that when used for applications such as electric and electronic parts, the physical properties of the molded article may be insufficient.

An object of the present invention is to provide a liquid crystal polymer composition capable of forming an article such as a molded product having improved metal adhesiveness while maintaining welding strength.

Means for solving problems

The present inventors conducted intensive research in view of the above-mentioned problems and found that by blending a compound containing a carbodiimide group (carbodiimide group) into a liquid crystal polymer and a cyclic olefin resin, the metal adhesion is improved while maintaining the welding strength of articles such as molded products, thereby completing the present invention.

That is, the present invention includes the following preferred aspects.

[1] A liquid crystal polymer composition comprising: 100 parts by mass of a liquid crystal polymer, 0.1 to 10 parts by mass of a cyclic olefin resin, and 0.1 to 5 parts by mass of a carbodiimide group-containing compound.

[2] The liquid crystal polymer composition of [1], wherein the liquid crystal polymer is a liquid crystal polyester resin comprising repeating units represented by formula (I) and formula (II):

[Chemical formula 1]

.

[3] The liquid crystal polymer composition of [1] or [2], wherein the liquid crystal polymer is a wholly aromatic liquid crystal polyester resin composed of repeating units represented by formula (I) to formula (IV):

[Chemical formula 2]

In the formula, Ar ₁ and Ar ₂ each represent a divalent aromatic group.

[4] The liquid crystal polymer composition described in [3], wherein Ar ₁ and Ar ₂ are each independently one or more aromatic groups selected from the group consisting of the aromatic groups represented by formulas (1) to (4):

[Chemical formula 3]

.

[5] The liquid crystal polymer composition according to [3] or [4], wherein _Ar1 is an aromatic group represented by formula (1), and _Ar2 is an aromatic group represented by formula (1) and/or (3).

[6] The liquid crystal polymer composition according to any one of [1] to [5], further comprising a needle-like filler.

[7] The liquid crystal polymer composition described in [6], wherein the needle-like filler is needle-like titanium oxide.

[8] The liquid crystal polymer composition according to [6] or [7], wherein the content of the needle-shaped filler is 1 to 100 parts by mass based on 100 parts by mass of the liquid crystal polymer.

[9] A molded article comprising the liquid crystal polymer composition according to any one of [1] to [8].

[10] The molded article described in [9], wherein the molded article is a component constituting one type selected from the group consisting of a connector, a switch, a relay, a capacitor, a coil, a transformer, a camera module, and an antenna.

Effects of the Invention

The liquid crystal polymer composition of the present invention is excellent in soldering strength and metal adhesion and therefore can be suitably used in various applications such as electric and electronic parts or automobile parts that are integrated by injection insert molding.

DETAILED DESCRIPTION

The liquid crystal polymer (hereinafter also referred to as LCP) used in the liquid crystal polymer composition of the present invention is a polyester or polyester amide that forms an anisotropic melt phase, and is not particularly limited as long as it is a substance called a thermotropic liquid crystal polyester or a thermotropic liquid crystal polyester amide in the technical field.

The properties of the anisotropic melt phase can be confirmed by conventional polarized light inspection using crossed polarizers (polarizers). More specifically, the confirmation of the anisotropic melt phase can be implemented by using a Leitz polarized light microscope and observing a sample placed on a Leitz hot stage at a magnification of 40 times under a nitrogen environment. The liquid crystal polymer in the present invention is a polymer that optically shows anisotropy, that is, a polymer that transmits light when inspected between crossed polarizers. If the sample is optically anisotropic, polarized light will be transmitted even in a stationary state.

The liquid crystal polymer used in the present invention preferably has a crystal melting temperature of 320 to 360° C., more preferably 335 to 345° C., and even more preferably 337 to 343° C., as measured by a differential scanning calorimeter.

It should be noted that in this specification and claims, "crystalline melting temperature" refers to the temperature obtained by measuring the peak temperature of the crystalline melting temperature when using a differential scanning calorimeter (DSC) at a heating rate of 20°C/min. More specifically, after observing the endothermic peak temperature (Tm1) observed when measuring a sample of a liquid crystal polymer under a heating condition of 20°C/min from room temperature, the sample is kept at a temperature 20 to 50°C higher than Tm1 for 10 minutes, and then the sample is cooled to room temperature under a cooling condition of 20°C/min, and the endothermic peak when measured under a heating condition of 20°C/min is observed again, and the temperature showing the top of the peak is taken as the crystalline melting temperature of the liquid crystal polymer. As a measuring machine, for example, Exstar6000 manufactured by Seiko Instruments can be used.

As polymerizable monomers constituting the constituent units of the liquid crystal polymer in the present invention, for example, aromatic hydroxycarboxylic acids, aromatic dicarboxylic acids, aromatic diols, aromatic aminocarboxylic acids, aromatic hydroxylamines, aromatic diamines, aliphatic diols, and aliphatic dicarboxylic acids can be cited. Such polymerizable monomers can be used alone or in combination of two or more. It is suitable to use a polymerizable monomer having at least one hydroxyl group and a carboxyl group.

The polymerizable monomer constituting the constituent unit of the liquid crystal polymer may be an oligomer in which one or more of the above compounds are bonded together, that is, an oligomer composed of one or more of the above compounds.

Specific examples of aromatic hydroxycarboxylic acids include 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 2-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 5-hydroxy-2-naphthoic acid, 7-hydroxy-2-naphthoic acid, 3-hydroxy-2-naphthoic acid, 4'-hydroxyphenyl-4-benzoic acid, 3'-hydroxyphenyl-4-benzoic acid, 4'-hydroxyphenyl-3-benzoic acid and their alkyl, alkoxy or halogen substituted products, and their acylated products, ester derivatives, ester-forming derivatives such as acyl halides. Among these, from the viewpoint of easily adjusting the heat resistance and mechanical strength of the obtained liquid crystal polymer and the melting point, it is preferred to select one or more compounds of 4-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid.

Specific examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, 1,6-naphthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid, 4,4'-dicarboxybiphenyl, 3,4'-dicarboxybiphenyl and 4,4"-dicarboxyterphenyl, alkyl, alkoxy or halogen-substituted products thereof, and ester derivatives thereof, ester-forming derivatives such as acid halides. Among these, from the viewpoint of effectively improving the heat resistance of the obtained liquid crystal polymer, preferably one or more compounds selected from terephthalic acid, isophthalic acid and 2,6-naphthalene dicarboxylic acid are used, and more preferably terephthalic acid and 2,6-naphthalene dicarboxylic acid are used.

Specific examples of aromatic diols include hydroquinone, resorcinol, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 3,3'-dihydroxybiphenyl, 3,4'-dihydroxybiphenyl, 4,4'-dihydroxybiphenyl, 4,4'-dihydroxybiphenyl ether and 2,2'-dihydroxybinaphthyl, their alkyl, alkoxy or halogen substituted products, and their acylated derivatives. Among these, from the viewpoint of excellent reactivity during polymerization, preferably one or more compounds selected from hydroquinone, resorcinol, 4,4'-dihydroxybiphenyl and 2,6-dihydroxynaphthalene, more preferably one or more compounds selected from hydroquinone, 4,4'-dihydroxybiphenyl and 2,6-dihydroxynaphthalene.

Specific examples of the aromatic aminocarboxylic acid include 4-aminobenzoic acid, 3-aminobenzoic acid, 6-amino-2-naphthoic acid, alkyl-, alkoxy- or halogen-substituted products thereof, and ester-forming derivatives thereof such as acylates, ester derivatives and acyl halides.

Specific examples of aromatic hydroxylamines include 4-aminophenol, N-methyl-4-aminophenol, 3-aminophenol, 3-methyl-4-aminophenol, 4-amino-1-naphthol, 4-amino-4'-hydroxybiphenyl, 4-amino-4'-hydroxybiphenyl ether, 4-amino-4'-hydroxybiphenyl methane, 4-amino-4'-hydroxybiphenyl sulfide, and 2,2'-diaminobinaphthyl, their alkyl, alkoxy or halogen substituted products, and their acylated products and other ester-forming derivatives. Among these, 4-aminophenol is preferred from the viewpoint of easily achieving a balance between the heat resistance and mechanical strength of the obtained liquid crystal polymer.

Specific examples of the aromatic diamine include amide-forming derivatives such as 1,4-phenylenediamine, 1,3-phenylenediamine, 1,5-diaminonaphthalene, 1,8-diaminonaphthalene, alkyl-, alkoxy- or halogen-substituted products thereof, and acylated products thereof.

Specific examples of aliphatic diols include ethylene glycol, 1,4-butanediol, 1,6-hexanediol, and acylated products thereof. In addition, a polymer containing aliphatic diols such as polyethylene terephthalate or polybutylene terephthalate can be reacted with the aromatic hydroxycarboxylic acid, aromatic dicarboxylic acid, aromatic diol, and acylated products thereof, ester derivatives, acyl halides, and the like.

Specific examples of aliphatic dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, fumaric acid, maleic acid, and hexahydroterephthalic acid. Among these, oxalic acid, succinic acid, adipic acid, suberic acid, sebacic acid, and dodecanedioic acid are preferred from the viewpoint of excellent reactivity during polymerization.

The polymerizable monomers forming the constituent units of the liquid crystal polymer in the present invention may also include dihydroxyterephthalic acid, 4-hydroxyisophthalic acid, 5-hydroxyisophthalic acid, trimellitic acid, 1,3,5-benzenetricarboxylic acid, pyromellitic acid or their alkyl, alkoxy or halogen substituted products, and their acylated products, ester derivatives, ester-forming derivatives such as acyl halides as other copolymer components within the scope of not impairing the purpose of the present invention. The amount of these polymerizable monomers used is preferably an amount of 10 mol% or less relative to all the constituent units constituting the liquid crystal polymer.

In the present invention, the liquid crystal polymer may also be a polymer containing a thioester bond within the scope of not impairing the purpose of the present invention. Examples of polymerizable monomers providing such bonds include mercapto aromatic carboxylic acids, aromatic dithiols, and hydroxy aromatic thiols. The content of these polymerizable monomers is preferably an amount of 10 mol% or less relative to all constituent units constituting the liquid crystal polymer.

The polymers obtained by combining these repeating units may include polymers that form anisotropic melt phases and polymers that do not form anisotropic melt phases, depending on the composition or composition ratio of the monomers and the sequence distribution of each repeating unit in the polymer. However, the liquid crystal polymers used in the present invention are limited to polymers that form anisotropic melt phases.

As the liquid crystal polymer used in the present invention, a liquid crystal polyester resin containing repeating units represented by formula (I) and formula (II) is preferably used because of its excellent fluidity and mechanical properties.

[Chemical formula 4]

As the liquid crystal polymer used in the present invention, a wholly aromatic liquid crystal polyester resin composed of repeating units represented by formulae (I) to (IV) is preferably used because of its excellent fluidity and mechanical properties.

[Chemical formula 5]

[In the formula, _Ar1 and _Ar2 each represent a divalent aromatic group.]

Here, formula (III) and formula (IV) may contain a plurality of Ar ₁ and Ar ₂ , respectively. In addition, the "aromatic group" means a 6-membered monocyclic or condensed aromatic group having 2 rings.

From the perspective of excellent fluidity and mechanical properties, _Ar1 and _Ar2 are each independently selected from at least one aromatic group represented by the following formulae (1) to (4). It is particularly preferred that _Ar1 is an aromatic group represented by formula (1), and _Ar2 is an aromatic group represented by formula (1) and/or formula (3).

[Chemical formula 6]

Specific examples of the combination of polymerizable monomers forming the constituent units of the liquid crystal polymer used in the present invention include the following.

1) 4-Hydroxybenzoic acid/6-Hydroxy-2-naphthoic acid,

2) 4-Hydroxybenzoic acid/terephthalic acid/4,4'-dihydroxybiphenyl,

3) 4-Hydroxybenzoic acid/terephthalic acid/isophthalic acid/4,4'-dihydroxybiphenyl,

4) 4-Hydroxybenzoic acid/terephthalic acid/isophthalic acid/4,4'-dihydroxybiphenyl/hydroquinone,

5) 4-Hydroxybenzoic acid/terephthalic acid/hydroquinone,

6) 6-Hydroxy-2-naphthoic acid/terephthalic acid/hydroquinone,

7) 4-Hydroxybenzoic acid/6-hydroxy-2-naphthoic acid/terephthalic acid/4,4'-dihydroxybiphenyl,

8) 6-Hydroxy-2-naphthoic acid/terephthalic acid/4,4'-dihydroxybiphenyl,

9) 4-Hydroxybenzoic acid/6-hydroxy-2-naphthoic acid/terephthalic acid/hydroquinone,

10) 4-Hydroxybenzoic acid/6-hydroxy-2-naphthoic acid/terephthalic acid/hydroquinone/4,4'-dihydroxybiphenyl,

11) 4-Hydroxybenzoic acid/2,6-naphthalene dicarboxylic acid/4,4'-dihydroxybiphenyl,

12) 4-Hydroxybenzoic acid/terephthalic acid/2,6-naphthalene dicarboxylic acid/hydroquinone,

13) 4-Hydroxybenzoic acid/2,6-naphthalene dicarboxylic acid/hydroquinone,

14) 4-Hydroxybenzoic acid/6-hydroxy-2-naphthoic acid/2,6-naphthalene dicarboxylic acid/hydroquinone,

15) 4-Hydroxybenzoic acid/terephthalic acid/2,6-naphthalene dicarboxylic acid/hydroquinone/4,4'-dihydroxybiphenyl,

16) 4-Hydroxybenzoic acid/terephthalic acid/4-aminophenol,

17) 6-Hydroxy-2-naphthoic acid/terephthalic acid/4-aminophenol,

18) 4-Hydroxybenzoic acid/6-hydroxy-2-naphthoic acid/terephthalic acid/4-aminophenol,

19) 4-Hydroxybenzoic acid/terephthalic acid/4,4'-dihydroxybiphenyl/4-aminophenol,

20) 4-Hydroxybenzoic acid/terephthalic acid/ethylene glycol,

21) 4-Hydroxybenzoic acid/terephthalic acid/4,4'-dihydroxybiphenyl/ethylene glycol,

22) 4-Hydroxybenzoic acid/6-hydroxy-2-naphthoic acid/terephthalic acid/ethylene glycol,

23) 4-Hydroxybenzoic acid/6-hydroxy-2-naphthoic acid/terephthalic acid/4,4'-dihydroxybiphenyl/ethylene glycol,

24) 4-Hydroxybenzoic acid/terephthalic acid/2,6-naphthalene dicarboxylic acid/4,4'-dihydroxybiphenyl.

Among these, liquid crystal polymers composed of constitutional units derived from the polymerizable monomer described in 10) are preferred.

The above-mentioned liquid crystal polymers may be used alone or as a mixture of two or more liquid crystal polymers.

One particularly preferred embodiment of the liquid crystal polymer used in the present invention is a wholly aromatic liquid crystal polyester resin composed of repeating units represented by the following formulae (A) to (E).

[Chemical formula 7]

[Wherein, p, q, r, s and t represent the composition ratio (mol %) of each repeating unit in the liquid crystal polyester resin, and satisfy the following conditions:

25≤p≤45;

2≤q≤10;

10≤r≤20;

10≤s≤20;

20≤t≤40;

r＞s;

p＋q＋r＋s＋t＝100. ]

Hereinafter, a method for producing the liquid crystal polymer used in the present invention will be described.

The method for producing the liquid crystal polymer used in the present invention is not particularly limited, and the liquid crystal polymer can be obtained by subjecting a polymerizable monomer to a known polycondensation method for forming an ester bond or an amide bond, such as a melt acidolysis method or a slurry polymerization method.

The melt acid hydrolysis method is a preferred method for producing the liquid crystal polymer used in the liquid crystal polymer composition of the present invention. The method is a method in which the polymerizable monomer is initially heated to form a molten solution of the reaction material, and then a condensation reaction is continued to obtain a molten polymer. It should be noted that in order to easily remove the volatile by-products (such as acetic acid, water, etc.) in the final stage of the condensation, a vacuum can also be applied.

The slurry polymerization method is a method of reacting polymerizable monomers in the presence of a heat exchange fluid, and a solid product is obtained in a state of being suspended in the heat exchange medium.

In either the melt acidolysis method or the slurry polymerization method, the polymerizable monomer used to produce the liquid crystal polymer may be subjected to the reaction at room temperature as a modified form (lower acyl group) in which the hydroxyl group and/or the amino group is acylated, that is, as a lower acylate.

The lower acyl group is preferably an acyl group having 2 to 5 carbon atoms, and more preferably an acyl group having 2 or 3 carbon atoms. In a preferred embodiment of the present invention, an acetylated product of the polymerizable monomer is subjected to the reaction.

The lower acylate of the polymerizable monomer may be one previously synthesized by acylation, or an acylating agent such as acetic anhydride may be added to the polymerizable monomer to generate the lower acylate in the reaction system during the production of the liquid crystal polymer.

In either the melt acidolysis method or the slurry polymerization method, the polycondensation reaction can be carried out usually at a temperature of 150 to 400° C., preferably 250 to 370° C., under normal pressure and/or reduced pressure, and a catalyst may be used as required.

Specific examples of catalysts include: organic tin compounds such as dialkyl tin oxides (e.g., dibutyl tin oxide) and diaryl tin oxides; titanium dioxide; antimony trioxide; organic titanium compounds such as alkoxytitanium silicates and titanium alkoxides; alkali metal and alkaline earth metal salts of carboxylic acids (e.g., potassium acetate); gaseous acid catalysts such as Lewis acids (e.g., boron trifluoride) and hydrogen halides (e.g., hydrogen chloride); and the like.

When a catalyst is used, the amount of the catalyst is preferably 1 to 1000 ppm, more preferably 2 to 100 ppm, based on the total amount of the polymerizable monomers.

The liquid crystal polymer obtained by such a polycondensation reaction is usually extracted from a polymerization reaction tank in a molten state, processed into a pellet, flake or powder form, and melt-kneaded with other components.

In order to improve heat resistance by increasing the molecular weight, the granular, flake, or powdery liquid crystal polyester may be heat-treated in a substantially solid phase under reduced pressure, vacuum, or in an atmosphere of nitrogen or helium as an inert gas.

The liquid crystal polymer composition of the present invention contains a cyclic olefin-based resin in addition to the above-mentioned liquid crystal polymer.

The cyclic olefin resin used in the liquid crystal polymer composition of the present invention includes polymers of cyclic olefins such as norbornene or polycyclic norbornene monomers, or copolymers thereof. The cyclic olefin resin may include an open-ring structure, or may be a resin obtained by hydrogenating a cyclic olefin resin including an open-ring structure. In addition, the cyclic olefin resin may also include structural units derived from chain olefins and vinyl aromatic compounds within a range that does not significantly impair transparency or significantly increase hygroscopicity. In addition, the cyclic olefin resin may also introduce polar groups into its molecules.

Examples of the chain olefin include ethylene and propylene, and examples of the vinylated aromatic compound include styrene, α -methylstyrene, and alkyl-substituted styrene.

When the cyclic olefin-based resin is a copolymer of a cyclic olefin and a chain olefin and/or a vinylated aromatic compound, the content of the structural unit derived from the cyclic olefin is usually 50 mol % or less, preferably 15 to 50 mol %, more preferably 20 to 45 mol %, and further preferably 25 to 40 mol % relative to all the structural units of the copolymer.

When the cyclic olefin resin is a terpolymer of a cyclic olefin, a chain olefin and a vinyl aromatic compound, the content of the structural unit derived from the chain olefin is usually 5 to 80 mol% relative to all the structural units of the copolymer, and the content of the structural unit derived from the vinyl aromatic compound is usually 5 to 80 mol% relative to all the structural units of the copolymer. In such a terpolymer, there is an advantage that the amount of expensive cyclic olefin used can be relatively reduced.

Cyclic olefin resins are commercially available. Examples of commercially available cyclic olefin resins include Topas (registered trademark) (Ticona, Germany), ARTON (registered trademark) (JSR), ZEONOR (registered trademark) (Zeon), ZEONEX (registered trademark) (Zeon), and Apel (registered trademark) (Mitsui Chemicals).

The content of the cyclic olefin resin in the liquid crystal polymer composition of the present invention is 0.1 to 10 parts by mass, preferably 0.5 to 8 parts by mass, more preferably 1 to 7 parts by mass, and further preferably 2 to 6 parts by mass, relative to 100 parts by mass of the liquid crystal polymer. By making the content of the cyclic olefin resin within the above range, the deterioration of the moldability due to the decrease in melt viscosity can be suppressed, while the welding strength can be maintained, and the metal adhesion of the molded product can be significantly improved.

The liquid crystal polymer composition of the present invention may further contain other resin components in addition to the above-mentioned cyclic olefin resins within the scope that does not impair the purpose of the present invention. Examples of other resin components include thermoplastic resins such as polyamide, polyester, polyacetal, polyphenylene ether and its modified products, polysulfone, polyethersulfone, polyetherimide, polyamideimide, etc.; or thermosetting resins such as phenolic resin, epoxy resin, polyimide resin, etc.

Other resin components may be contained alone or in combination of two or more. The content of other resin components is not particularly limited and can be appropriately determined according to the use or purpose of the liquid crystal polymer composition. Typically, the total content of other resins is preferably added in the range of 0.1 to 100 parts by mass, more preferably 0.2 to 80 parts by mass, relative to 100 parts by mass of the liquid crystal polymer.

The liquid crystal polymer composition of the present invention contains a carbodiimide group-containing compound in addition to the above-mentioned liquid crystal polymer and cyclic olefin resin.

The carbodiimide group-containing compound used in the liquid crystal polymer composition of the present invention refers to a compound having a carbodiimide group (-N=C=N-), and is not particularly limited as long as it is a compound having at least one carbodiimide group.

Examples of the carbodiimide group-containing compound include a polycarbodiimide compound and a monocarbodiimide compound.

Specific examples of the polycarbodiimide compound include aromatic polycarbodiimides such as poly(4,4'-diphenylmethanecarbodiimide), poly(p-phenylenecarbodiimide), poly(m-phenylenecarbodiimide), poly(diisopropylphenylcarbodiimide), and poly(triisopropylphenylcarbodiimide); and alicyclic polycarbodiimides such as poly(dicyclohexylmethanecarbodiimide).

Examples of the monocarbodiimide compound include aromatic monocarbodiimide compounds such as diphenylcarbodiimide, di-2,6-dimethylphenylcarbodiimide, di-2,6-diethylphenylcarbodiimide, di-2,6-diisopropylphenylcarbodiimide, di-2,6-di-tert-butylphenylcarbodiimide, di-o-tolylcarbodiimide, di-p-tolylcarbodiimide, di-2,4,6-trimethylphenylcarbodiimide, di-2,4,6-triisopropylphenylcarbodiimide, and di-2,4,6-triisobutylphenylcarbodiimide; alicyclic monocarbodiimide compounds such as di-cyclohexylcarbodiimide and di-cyclohexylmethanecarbodiimide; and aliphatic monocarbodiimide compounds such as di-isopropylcarbodiimide and di-octadecylcarbodiimide.

The carbodiimide group-containing compound may be used alone or in combination of two or more thereof. Among these, a preferred specific compound is an aliphatic polycarbodiimide compound, and commercially available products thereof include, for example, CARBODILITE (registered trademark) HMV-8CA or CARBODILITE (registered trademark) LA-1 manufactured by Nisshinbo Chemical Co., Ltd.

The content of the carbodiimide group-containing compound in the liquid crystal polymer composition of the present invention is 0.1 to 5 parts by mass, preferably 0.3 to 4 parts by mass, more preferably 0.5 to 3 parts by mass, and further preferably 0.7 to 2.5 parts by mass relative to 100 parts by mass of the liquid crystal polymer. By making the content of the carbodiimide group-containing compound within the above range, the deterioration of the moldability caused by the decrease in melt viscosity can be suppressed, while the welding strength can be maintained, and the metal adhesion of the molded product can be significantly improved.

The liquid crystal polymer composition of the present invention preferably further contains a needle-shaped filler. Examples of the needle-shaped filler include calcium silicates such as wollastonite, MOS・HIGE (Fibrous Magnesium Oxysulfate, モスハイジ), xonotlite, calcium titanate, aluminum borate, needle-shaped calcium carbonate, needle-shaped titanium oxide, tetrapod-type zinc oxide, etc. Needle-shaped titanium oxide is preferred from the perspective of excellent mechanical strength. The needle-shaped filler can be used alone or in combination of two or more.

The content of the needle-shaped filler in the liquid crystal polymer composition of the present invention is preferably 1 to 100 parts by mass, more preferably 3 to 70 parts by mass, further preferably 4 to 50 parts by mass, and particularly preferably 5 to 20 parts by mass relative to 100 parts by mass of the liquid crystal polymer. By containing the needle-shaped filler within the above range, the particles generated during ultrasonic cleaning of the molded product can be reduced.

The liquid crystal polymer composition of the present invention may contain, in addition to the above-mentioned needle-shaped filler, other inorganic fillers or organic fillers in the form of fibers, plates or particles, within a range not impairing the effects of the present invention.

When the liquid crystal polymer composition of the present invention contains an inorganic filler or an organic filler other than the needle-shaped filler, the content thereof is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass, relative to 100 parts by mass of the liquid crystal polyester. If the content of these other fillers exceeds the above upper limit, there is a tendency for the molding processability to decrease or the thermal stability to deteriorate.

Examples of other fibrous fillers include ground glass, silica alumina fibers, alumina fibers, carbon fibers, aramid fibers, polyarylate fibers, polybenzimidazole fibers, potassium titanate whiskers, and aluminum borate whiskers. These may be used alone or in combination of two or more.

Examples of other plate-like fillers include talc, mica, kaolin, clay, vermiculite, feldspar powder, acid clay, wax clay, sericite, stevensite, bentonite, glass flakes, slate powder, silicates such as silane, calcium carbonate, lead carbonate (basic lead carbonate), barium carbonate, magnesium carbonate, carbonates such as dolomite, barite powder, precipitated calcium sulfate, plaster of Paris (calcined gypsum), sulfates such as barium sulfate, hydroxides such as hydrated aluminum oxide, aluminum oxide, antimony oxide, magnesium oxide, plate-like titanium oxide, zinc white, silicon dioxide, silica sand, quartz, white carbon, oxides such as diatomaceous earth, sulfides such as molybdenum disulfide, plate-like wollastonite, and the like. These may be used alone or in combination of two or more.

Examples of other particulate fillers include calcium carbonate, glass beads, barium sulfate, and particulate titanium oxide. These may be used alone or in combination of two or more.

Furthermore, the liquid crystal polymer composition of the present invention may contain additives other than those described above within a range not impairing the effects of the present invention.

As other additives, for example, higher fatty acids, higher fatty acid esters, higher fatty acid amides, higher fatty acid metal salts (here, higher fatty acids refer to, for example, fatty acids with 10 to 25 carbon atoms), fluorocarbon surfactants, etc. as lubricants, polysiloxanes, fluororesins, etc. as mold release improvers, dyes, pigments, carbon black, etc. as colorants, flame retardants, antistatic agents, surfactants, phosphorus antioxidants, phenolic antioxidants, sulfur antioxidants, etc. as antioxidants, weathering agents, heat stabilizers, neutralizers, etc. As for additives with external lubricant effects, such as higher fatty acids, higher fatty acid esters, higher fatty acid metal salts, and fluorocarbon surfactants, they can also be attached to the particle surface of the liquid crystal polymer composition in advance when the liquid crystal polymer composition is molded. These additives can be used alone or in combination of two or more.

The content of these other additives is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, relative to 100 parts by mass of the liquid crystal polymer. If the content of these other additives exceeds the upper limit, there is a tendency for the molding processability to decrease or the thermal stability to deteriorate.

Liquid crystal polymer, cyclic olefin resin and carbodiimide-containing compound, as well as other inorganic fillers and/or organic fillers, other additives or other resin components as required, are blended in a prescribed composition and melt-kneaded using a Banbury mixer, kneader, single-screw or twin-screw extruder, etc., thereby producing the liquid crystal polymer composition of the present invention.

The liquid crystal polymer composition of the present invention thus obtained can be molded or processed by a known molding method such as an injection molding machine or an extruder to obtain a desired molded article.

The molded article composed of the liquid crystal polymer composition of the present invention has improved metal adhesion while maintaining soldering strength, and is therefore suitable for electronic parts such as connectors, switches, relays, capacitors, coils, transformers, camera modules, and antennas.

Example

The present invention is described below by way of examples, but the present invention is not limited to the following examples. It should be noted that the melt viscosity, load deflection temperature, tensile strength, flexural strength, number of particles generated, weld strength, and metal adhesion in the examples were measured and evaluated according to the methods described below.

(Melt viscosity)

The melt viscosity of each sample at the crystal melting temperature (Tm) + 20°C was measured using a melt viscosity measuring apparatus (Capillograph 1D manufactured by Toyo Seiki Co., Ltd.) using a 1.0 mmφ×10 mm capillary at a shear rate of 1000 sec ^-1 .

(Load deflection temperature)

Strip test pieces (length 127 mm × width 12.7 mm × thickness 3.2 mm) were molded using an injection molding machine (UH1000-110 manufactured by Nissei Plastic Industries, Ltd.), and the temperature at which a specified deflection amount (0.254 mm) was reached was measured in accordance with ASTM D648 at a load of 1.82 MPa and a heating rate of 2°C/min.

(Tensile Strength)

An injection molding machine (UH1000-110 manufactured by Nissei Plastic Industry Co., Ltd.) was used to perform injection molding at a barrel temperature of 20 to 40°C above the crystal melting temperature and a mold temperature of 70°C to produce an ASTM No. 4 dumbbell test piece. The test was performed using INSTRON 5567 (universal testing machine manufactured by Instron Japan Company Limited) in accordance with ASTM D638.

(Bending Strength)

The deflection temperature under load was measured in accordance with ASTM D790 using the same test piece as that used for measuring the deflection temperature under load.

(Number of particles generated)

The same test piece as the test piece for measuring the load deflection temperature was placed in a cylindrical glass container with an outer diameter of 50 mm, an inner diameter of 45 mm, and a height of 100 mm with 50 mL of pure water so that the gate portion was not immersed in water. Then, the cylindrical glass container was placed in an ultrasonic cleaning tank (US-102 manufactured by SND Co., Ltd.) with a length of 140 mm, a width of 240 mm, and a depth of 100 mm with 1000 mL of water. Ultrasonic cleaning was performed for 10 minutes at an output power of 100 W at 38 kHz. After that, the number of particles with a particle size of 2 μm or more (droplets (particles) peeled off from the test piece) contained in 1 mL of pure water was measured three times using a particle counter (LiQuilaz-05 manufactured by Specllis Co., Ltd.), and the average value was used as the measurement result.

(Welding strength)

Using an injection molding machine (NEX15-1E manufactured by Nissei Plastic Industry Co., Ltd.) with a clamping pressure of 15t, injection molding was performed at a barrel temperature of melting point +20~40°C and a mold temperature of 70°C to produce cylindrical test pieces with welded parts (thickness 0.8mm, outer diameter 10mm, height 5mm). For each test piece, a compression test was performed using INSTRON5567 (universal testing machine manufactured by Instron Japan Company Limited) to measure the strength of the welded part when it broke.

(Metal Adhesion)

A metal rivet (12 mm in diameter, 8 mm in height) coated with 12 mg of adhesive material (AE-421D manufactured by Ajinomoto Fine Techno Co., Ltd.) was attached to the same test piece as the test piece for measuring the load deflection temperature at a position 10 mm opposite to the gate, and heated at 80°C for 30 minutes to cure the adhesive material to prepare an adhesion evaluation test piece. For each test piece, the metal rivet and the test piece were stretched horizontally using INSTRON 5567 (universal testing machine manufactured by Instron Japan Company Limited) to measure the adhesion.

In Examples and Comparative Examples, the following abbreviations represent the following compounds.

POB: para-hydroxybenzoic acid;

BON6: 6-hydroxy-2-naphthoic acid;

HQ: hydroquinone;

BP: 4,4'-dihydroxybiphenyl;

TPA: terephthalic acid.

[Synthesis Example 1 (LCP)]

Into a reaction vessel equipped with a stirring device with a torque meter and a distillation tube, POB, BON6, HQ, BP and TPA were charged according to the composition ratio shown in Table 1 to give a total amount of 6.5 mol, and acetic anhydride was further charged in an amount of 1.03 times the molar amount of hydroxyl groups (moles) of the total monomers, and deacetylation polymerization was carried out under the following conditions.

The temperature was raised from room temperature to 150°C in a nitrogen atmosphere in 1 hour and maintained at the same temperature for 30 minutes. Then, the temperature was raised to 350°C in 7 hours while distilling off the by-produced acetic acid, and then the pressure was reduced to 5 mmHg in 80 minutes. The polymerization reaction was terminated at the time when the specified torque was shown, the contents were taken out from the reaction vessel, and the particles of the liquid crystal polyester resin were obtained by a pulverizer. The amount of distilled acetic acid during polymerization was approximately as shown in the theoretical value.

[Table 1]

POB BON6 HQ BP TPA Weight(g) 323.2 48.9 114.5 169.4 323.9 Mole % 36 4 16 14 30

The fillers used in the following examples and comparative examples are shown.

Cyclic olefin resin (COP): Cyclic olefin polymer "ZEONOR (registered trademark) 1420R" manufactured by Zeon Co., Ltd. of Japan;

Carbodiimide group-containing compound (CI): polycarbodiimide "CARBODILITE (registered trademark) LA-1" manufactured by Nisshinbo Chemical Co., Ltd.;

Needle-shaped filler: needle-shaped titanium oxide "FTL-400" manufactured by Ishihara Industry Co., Ltd.

Examples 1 to 5, Comparative Examples 1 to 4

The LCP synthesized in Example 1, cyclic olefin resin (COP), carbodiimide-containing compound (CI) and needle-shaped filler were mixed to the content described in Table 2, and melt-kneaded at 350°C using a twin-screw extruder (TEX-30 manufactured by Nippon Steel Co., Ltd.) to obtain particles of a liquid crystal polymer composition. The melt viscosity, load deflection temperature, tensile strength, bending strength, number of particles generated, welding strength, and metal adhesion were measured and evaluated using the above method. The results are shown in Table 2.

As shown in Table 2, the liquid crystal polymer compositions of Examples 1 to 5 are all compositions having excellent metal adhesiveness while maintaining soldering strength.

In contrast, regarding the liquid crystal polymer compositions of Comparative Examples 1 to 4, it was confirmed that: the deterioration of moldability due to the decrease in melt viscosity (deterioration in metering stability, blistering due to air entrapment, etc.), the decrease in welding strength, or the decrease in metal adhesion, are not preferred compositions as molding materials.

In addition, the liquid crystal polymer compositions of Examples 4 and 5 in which a predetermined amount of needle-shaped filler was blended were compositions in which generation of fine particles was suppressed.

[Table 2]

.

Claims (5)

1. A liquid crystalline polymer composition comprising: 100 parts by mass of a liquid crystal polymer, 2 to 6 parts by mass of a cyclic olefin resin and 0.7 to 2.5 parts by mass of a carbodiimide group-containing compound,

The liquid crystal polymer is a wholly aromatic liquid crystal polyester resin composed of repeating units represented by the formulae (a) to (E):

[ chemical formula 1]

Wherein p, q, r, s and t represent the composition ratio in the liquid crystal polyester resin of each repeating unit, the unit of the composition ratio is mol%, and the following condition is satisfied:

25≤p≤45；

2≤q≤10；

10≤r≤20；

10≤s≤20；

20≤t≤40；

r＞s；

p+q+r+s+t＝100，

The cycloolefin resin is a polymer of norbornene or polycyclic norbornene monomer or a copolymer thereof,

The carbodiimide group-containing compound is a cycloaliphatic polycarbodiimide.

2. The liquid crystal polymer composition of claim 1, further comprising acicular titanium oxide.

3. The liquid crystal polymer composition according to claim 2, wherein the needle-like titanium oxide is contained in an amount of 1 to 100 parts by mass based on 100 parts by mass of the liquid crystal polymer.

4. A molded article comprising the liquid crystal polymer composition according to any one of claims 1 to 3.

5. The molded article according to claim 4, wherein the molded article is a member constituting 1 kind selected from a connector, a switch, a relay, a capacitor, a coil, a transformer, a camera module, and an antenna.